It's pretty cool, but by the time you start adding the costs of the software, the interface board, the probes, to get everything running and then throw in that you need a computer always on in your fish room to acquire data, I'd say you're better off with an Aquacontroller 3.
As mentioned, it's an antiquated parallel interface which means that it will have a maximum of 15 feet with 12 being safer for data. 15 feet of cable doesn't go very far, so you're talking about having a computer pretty much right next to your aquarium.
Neat for the DIY tinkerer with a computer to spare.